cellulose–hemicellulose–lignin
ChemistryBois is specified as cellulose–hemicellulose–lignin. Density band 0.3–0.8 g/cm³ typical.
What holds Bois together is not the nickname. Formula cellulose–hemicellulose–lignin, density 0.3–0.8 g/cm³ typical.
Meters are atlas-relative. Grades are the SKUs buyers write.
Phases
Microstructure
OrderProcessing sets grain, crystallinity or fibre orientation — the reason two lots of Bois can test differently.
Interfaces
SurfacesCoatings, oxide films, sizings or paper faces often decide weather and fire behaviour more than the bulk brochure.
Defects
FlawsInclusions, voids, knots, pinholes or residual stress start the failures that mill certificates do not list.
Grades
VariantsBois is a family. Grade names below are the ones buyers actually write on RFQs.
Ageing
TimeMoisture, UV, creep, hydrogen or carbonation shift properties in service. Design to the aged state.
Jauges relatives
Strength54
Strength is an editorial 0–100 mark relative to the other 31 materials in this atlas — not a laboratory certificate.
Heat envelope32
Heat envelope is an editorial 0–100 mark relative to the other 31 materials in this atlas — not a laboratory certificate.
Fire behaviour34
Fire behaviour is an editorial 0–100 mark relative to the other 31 materials in this atlas — not a laboratory certificate.
Insulation56
Insulation is an editorial 0–100 mark relative to the other 31 materials in this atlas — not a laboratory certificate.
Workability88
Workability is an editorial 0–100 mark relative to the other 31 materials in this atlas — not a laboratory certificate.
Circularity76
Circularity is an editorial 0–100 mark relative to the other 31 materials in this atlas — not a laboratory certificate.
Nuances
SPF dimensional
North American studs.North American studs.
Oak / teak hardwoods
Joinery, decks.Joinery, decks.
CLT
Mass timber plates.Mass timber plates.
Glulam
Beams and arches.Beams and arches.
Fire-retardant treated
Interior codes.Interior codes.
Liaisons
Primary bonding
Bois holds together by ionic/covalent networks.
Secondary forces
Hydrogen bonds, van der Waals stacks or grain-boundary cohesion set toughness and moisture uptake.
Composites & fills
Fillers, fibres, plasticisers or aggregates are part of the real product, not impurities.
Environment film
Oxides, chars, sizings or paints are the layer the world actually meets.
Change the grade, the coating or the moisture and you have a different material with the same English name.